1. Field of Technology
This invention relates to fire fighting garments, and more specifically, to a two layer garment system that combines a Basofil outer layer with a trilaminate inner liner.
2. Related Art
A firefighter garment must withstand severe conditions of heat and moisture in order to protect the wearer. Accordingly, the National Fire Protection Association (xe2x80x9cNFPAxe2x80x9d) has established many standards for firefighter garments to ensure the safety of firefighters and emergency first responders. For example, a firefighter garment must have a thermal protective performance (xe2x80x9cTPPxe2x80x9d) of at least thirty five (35) and all components of the firefighter garment must be fire retardant.
Conventional firefighter garments have an outer shell and an inner liner. The inner liner has two layers: (1) a moisture barrier layer being a bilaminate of a moisture barrier fabric, e.g., GORE-TEX(copyright) by W. L. Gore and Associates, Inc., and a stiffening fabric, and (2) a quilted thermal layer made of two to four layers of material. These two layers of the inner liner are sewn together into a single inner liner and the seams are sealed with tape to prevent any leakage through the stitching holes. In constructing a firefighting garment, the outer shell and the inner liner are each made into the desired firefighting garment, such that the inner liner is mechanically fastened, e.g., zippers, buttons, snaps, or clasps, inside the outer liner with the quilted thermal layer being closest to the wearer. The inner liner is made as a separate garment to facilitate its removal from the garment for cleaning.
There are several disadvantages with conventional firefighting garments. First, because the quilted thermal layer typically lays closest to the wearer""s body, it impedes transport of moisture vapor, i.e., sweat, from the wearer""s skin until it can pass through the breathable moisture barrier layer. This sweating process is the primary cooling mechanism for the human body and any reduction of this process has serious, and potentially fatal, consequences. An increase of breathable levels of a firefighting garment, which means the ability of a garment to transfer the heat laden sweat vapor from the skin to the air outside the garment, is a vital concern. Second, the quilted thermal layer of the inner liner tends to become very heavy and contaminated with germs and bacteria as it holds moisture and sweat from the wearer. Third, once laden with moisture, the quilted thermal layer does not breathe very easily. Fourth, manufacturing of a firefighting garment is costly and time consuming due to the separate manufacturing of the outer shell and the inner liner and the need to mechanically fasten these two together.
While single layer trilaminates have been successfully in use for some time as protective garments, and specifically as rainwear, the use of a trilaminate material as an inner liner in conjunction with an outer layer, thereby creating a two layer firefighting garment, has not been produced. Therefore, there is a need for a firefighter garment that is light-weight and allows moisture to xe2x80x9cbreathexe2x80x9d through the garment layers. There is a further need for a firefighter garment that provides the necessary thermal layer while eliminating the need for quilting of multiple layers of fabric.
In about 1997, W. L. Gore and Associates, Inc. began promoting a new trilaminate fabric called Crosstech S/R which was intended to meet the Federal Emergency Management Authority (xe2x80x9cFEMAxe2x80x9d) requirements for search and rescue and be a high performance single-layer garment. This trilaminate fabric has a TPP rating of twenty-one (21). The disadvantage with the Crosstech S/R trilaminate fabric is that it is very expensive, thereby making it not economically feasible to incorporate the Crosstech S/R fabric into firefighter garments. Other less expensive trilaminate fabrics, e.g., Nomex, are available. However, the TPP ratings of such trilaminates are much lower than that of Crosstech S/R due to the thermal decomposition of the fabric. Specifically, these cheaper trilaminates have premature moisture membrane failure at high temperatures, thereby making it unsafe to use these trilaminates in a firefighter garment.
Therefore, there is a need for a relatively inexpensive and light-weight trilaminate fabric having the higher thermal stability needed for a firefighting garment.
In its continuous desire to provide better firefighting garments, BASF company began developing a fabric called Basofil that typically displays a higher TPP rating than competitive or comparable fabrics. Basofil fabrics have high insulation values due to their nonconductive nature and display endothermic or heat absorbing characteristics during thermal decomposition.
Therefore, there is a need for a light-weight fabric that uses Basofil, or a comparable fabric, in both the outer shell and the inner liner layers, thereby maximizing the TPP of the resulting fabric while maintaining its light weight and moisture barrier qualities.
In U.S. Pat. No. 5,640,718 to Aldridge (xe2x80x9cthe Aldridge Patentxe2x80x9d), a fire fighter garment is disclosed having an outer layer and an inner liner, wherein the inner liner is two layers with the thermal layer (which is against the wearer in conventional garments) repositioned to be closest to the outer layer and the moisture barrier layer is against the wearer. The moisture barrier layer is laminated with a face cloth that is to be worn directly against the wearer. The thermal layer is also a bilaminate of quilted fabrics and a foam layer.
The principal disadvantage with the Aldridge Patent is that it uses an inner liner having a laminated foam thermal layer. Therefore, this construction retains the bulk associated with conventional fire fighting garments. In addition, although repositioning the moisture barrier layer to the inner layer next to the wearer facilitates the garment""s breathing, this effort is defeated by the use of closed cell foam in the thermal layer which is non-vapor permeable. Efforts to increase breathability by aperturing the foam is only marginally effective as tests have shown. However, in this configuration a trilaminate is not used in the finished firefighting garment. The moisture barrier layer fulfills the role of face cloth but is still in bilaminate form.
The present invention solves the problems associated with conventional firefighting garments and textile products by using a two layer garment system having an outer layer and an inner liner. The outer layer contains a Basofil blend and the inner layer is a trilaminate comprised of a means for insulating, a means for water proofing, and a means for providing a face cloth. In the preferred embodiment, the means for insulating is a layer containing a Basofil blend knit laminated to the means for water proofing; the means for water proofing contains a commercially available moisture membrane, e.g, GORE-TEX(copyright) or Stedair 2000(copyright), laminated to the means for providing a face cloth, and the means for providing a face cloth contains a Nomex knit. Once the inner liner is made, it is sewn into an outer shell of a firefighting garment. Finally, all construction seams of the final firefighting garment are sealed according to manufacturers"" guidelines to maintain the moisture integrity of the garment.
There are many advantages with the two layer garment system of the present invention. A garment employing the present invention is thinner and less bulky than conventional firefighting garments because of the elimination of a quilted inner liner. Also, such a garment can be lighter than conventional garments in construction, and also in use, in as much as it has much less moisture weight gain potential over conventional composites. Most importantly, a firefighting garment employing the present invention has a TPP rating of at least 35.
Due to the construction necessities, conventional firefighting garments have layers that are typically snapped or zipped together. It is this mechanical joining of layers that also adds weight, as well as bulk, to such a garment. In manufacturing, a conventional garment is made as two pieces that are later joined together, thereby adding to the manufacturing time and cost of the garment. By simplifying construction and eliminating the mechanical interfacing of conventional garments, the present invention saves both time and expense because a firefighting garment can be manufactured as a single unit.
The two layer garment system of the present invention also increases the breathability of the resulting garment because the moisture membrane in the inner layer is positioned closer to the wearer. In addition, with the elimination of the thermal layer, better breathability is achieved because there is no absorption of excess water. Lastly, the means for insulating the inner layer of the present invention does not depend on a lofted or batting material which can be compressed or lost upon extended use. Therefore, the two layer garment system of the present invention will not have a loss of insulation levels.